Handover In Gsm-r Networks Of The High Speed Railway System

In order to resolve the hard handover problems in the GSM-R network, the performance assess technology and test methods for existing handover technology are studied. A handover performance evaluation method based on signal level is given to evaluate the overall performance for handover algorithm. Moreover, a novel handover method based on double antenna technology is proposed in this thesis, which results in a seamless handover. Thus, the handover performance is improved in GSM-R as well as the safety and reliability of the high-speed rail system.First, a deep survey of the existing handover technologies and research status are introduced. We get a clear principle of handover and handover performance impact factors which including radio propagation model, coverage model and the speed of trains. According to the performance evaluation standard proposed by the UIC, a detail discussion on the interruption time and the success rate which are related to the link layer and the test methods of the two indicators respectively are presented. Furthermore, a method of handover performance evaluation based on the signal level is proposed to evaluate the overall performance of handover algorithm.And then, we investigate the hard handover problems and take the special circumstances characteristics including the high speed move, the trajectory known in advance and the lager length of the train into account. A dual-antenna handover scheme is proposed. The feasibility of this scheme is analyzed and the principle and resources allocation issue are discussed. The process of this scheme is described and the performance of the Dual-antenna handover is evaluated. It shows that this scheme can reduce the handover interrupt time and improve the handover success rate. Additionally, this strategy can avoid the "ping-pang" effect effectively. So the safety and reliability of the high-speed rail system is improved by the Dual-antenna handover in GSM-R.